DD分解炉燃烧与分解耦合过程的数值模拟  

Numerical simulation of coupling mechanism between pulverized coal combustion and calcium carbonate decomposition in double-sprayed precalciner

作　　者：梅书霞[1] 谢峻林[1] 何峰[1] 金明芳[1] 

机构地区：[1]武汉理工大学材料科学与工程学院,湖北武汉430070

出　　处：《化工学报》2013年第3期897-905,共9页CIESC Journal

基　　金：国家'十二五'科技支撑计划项目(2011BAE29B01);中央高校基本科研业务费专项资金项目~~

摘　　要：针对一实际尺寸的DD分解炉进行了煤燃烧与碳酸钙分解耦合过程的三维数值模拟研究,其中,对连续相采用Euler坐标系下的k-ε双方程湍流模型,采用离散相模型(discrete phase model)进行颗粒相的运动轨迹计算,采用组分运输模型(species transport model)结合涡耗散概念模型(EDC)模拟煤粉燃烧及生料分解过程,采用P-1辐射模型计算气体和颗粒之间的辐射换热。计算所得煤粉燃烬率为86%,碳酸钙分解率为92.9%,与工程实际数据吻合较好,表明模拟结果的可信性。研究结果表明:来自底部向上运动的高速烟气流与两股横向三次风相遇后,汇合成一股高速向上运动的主气流,携带着煤粉流在分解炉中心处向上运动,并偏向位于分解炉侧面的出口方向;煤粉的燃烧主要发生在分解炉下半柱体部分中心处,并形成了高温区;碳酸钙则围绕着高温区迅速分解,其分解过程主要发生在分解炉下半柱体部分。To study the coupling mechanism between combustion of pulverized coal and thermal decomposition of calcium carbonate, numerical simulation was carried out aiming at an actual double- sprayed precalciner. In Euler coordinate system gas phase was expressed with the k-ε two-equation model, in Lagrange coordinate system solid phase was expressed with the discrete phase model （DPM）, chemical reaction was expressed with the species transport model, and radiation was expressed with the P-1 radiation model. The predicted burn-off rate of pulverized coal was 86 %, and the predicted decomposition rate of calcium carbonate was 92.9%. The data were in agreement with actual measurement. The results showed that when vertical high-velocity flue gas from the kiln met horizontal tertiary air, a major upward gas stream was created, by which coal particle stream was carried toward the outlet located on the side of the precalciner. Combustion of pulverized coal occurred mainly in the center of the lower semi-cylindrical part of the precalciner, resulting in a high temperature zone, around which calcium carbonate decomposed rapidly.

关 键 词：分解炉 煤燃烧 碳酸钙分解 耦合 数值模拟 

分 类 号：TQ172[化学工程—水泥工业]